New Mavic Cosmic CXR 80 Aero Road Wheels

Mavic’s just introduced an all-new aerodynamic wheel/tire system called the CXR 80 that claims to have the lowest drag of any wheel setup in the world.

There are a few aero wheels that take tire shape into consideration, but Mavic goes a step further by incorporating the tire shape and design into the wheel, then fitting a plastic blade into a channel on the rim to seal the gap between tire and brake track.

The result is a near perfectly smooth surface that, combined with rim shaping, claims to provide superior aerodynamics in winds with up to an 18° yaw angle. Video above covers some of the development process, pics and more after the break…

The CXR was in development for three years. After developing the rim shape, they designed the sleeve to close the gap between tire’s edge and the tire. Lastly, even the tubular tire’s shape was dictated by aerodynamics, as was the tread. The front Yksion CXR tire’s tread pattern is shaped to manage the boundary layer of air (the air directly touching the tire and rim).

One of their design goals was to minimize surface turbulence to keep the air layers closest to the boundary layer laminar and close to the wheel/tire. Combined, the system claims to maintain laminar air flow from 0° to 18° of crosswind, which Mavic claims is the highest angle of any wheel. Beyond 18° you start to see some turbulence.

With more and more attention being paid to aerodynamics, Mavic will be making a big push with these wheels for triathlon in particular. Yes, they’ll be used by sponsored teams for time trials, too, but for the consumer market, 80mm is more in the realm of triathletes’ bikes.

Their wind tunnel testing shows they’re faster than their main competitors both alone on the bike and with a rider aboard. They’ve invited us out to test that in person in the wind tunnel in July, so look for a followup against some similarly deep wheels this summer.

SPECS AND DETAILS

The wheels use 16/20 stainless steel bladed, double butted spokes. Rims are very wide, and the CX01 Blades completely close any dips or gaps between rim and tire. The CXR system tires are 23mm wide and, as Mavic says, represents about 85% of the frontal surface area. That’s a large amount, so it only made sense to incorporate their design into the overall aerodynamics equation.

The rims are 27mm wide. The CX01 Blades (red in top left image) slot into a groove at the outer circumference with a soft flap that lays flat against the tire and can deform with the tire. Mavic’s US PR manager Zach Vestal says its somewhat elastic and is good for four or five installation and removals before they lose their shape and need to be replaced. Should they come off, Vestal says they tear apart easy enough not to get tangled up and cause an accident. New CXR tires will come with fresh blades.

Mavic says there are two NACA aero shape profiles that provide the least drag among shapes that would work within a bicycle frame – 0024 (aqua blue, top) and 0011 (green, bottom). They shaped the rim/blade/tire system to mimic the 0024 shape on the leading edge of the wheel and the 0011 on the trailing edge.

Weights are 995g front and 1175g rear and include the tire and blade. Total is 2,170g for the pair as a complete system. Wheels-only weight is 1630g for the pair.

Combined, Mavic says they’re good for saving up to 1.25 seconds per kilometer against the closest competitor, or 25 watts, with a massive crosswind. On a calm day with little wind, it’ll save about 6.4 watts and about 1/3 of a second faster per kilometer. Interestingly, at 14° to 19°, Mavic’s data shows they actually have negative drag and help boost speed!

Price for the complete system is $2,800 with skewers, wheel bags, low profile yellow SwissStop brake pads. Yes, they’re Shimano 11-speed compatible, as we predicted would be the case for all current Mavic wheels.

correct me if i am wrong, but i am not seeing negative drag in the data supplied. it is a great idea and looks like a stellar product. lets see how we can go with uci regulations…

Gyro2 - 06/20/12 - 6:23am

Cycling continues to attempt to become more about the equipment and less about the rider.

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